Erasable phase change optical recording elements

Abstract

A rewriteable phase-change optical recording element includes a substrate; and a recording layer over the substrate having at least two sub-layers of different chemical compositions, the compositions and thickness of the sub-layers being selected so that when subject to laser light during a writing process the compositions mixed together to form a high reflectivity mixed crystalline region without using any prior initialization or mixing processes.

What is claimed is:  
     
       1. A rewriteable phase-change optical recording element comprising: 
       (a) a substrate; and  
       (b) a recording layer over the substrate having at least a sub-layer comprising substantially Sb and a comprising TeIn m  wherein 0.063>m>0.15; the thickness of the sub-layers being selected so that when subject to laser light during a writing process the composition mix together to form a high reflectivity crystalline region without using any initialization or mixing processes prior to the writing processes.  
     
     
       2. The rewriteable phase-change optical recording element according to  claim 1  wherein the first sub-layer is adjacent to the substrate and is crystalline in structure prior to mixing. 
     
     
       3. The rewriteable phase-change optical recording element according to  claim 1  wherein the composition of the recording layer after mixing the sub-layer is represented by the formula Sb 1-x-mx Te x In mx  wherein 0.63≧m≧0.15, and 0.35≧x≧0.28. 
     
     
       4. A method for recording on a rewriteable phase-change optical recording element according to  claim 1  comprising pulsing the laser light between at least three power levels wherein both the highest power level and the second highest power lever cause the sub-layers to melt, mix together and solidify.